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Two accurate and efficient reversed-phase methods, one by high-performance thin-layer chromatography with ultraviolet‒visible detection (RP-HPTLC‒UV/VIS) and the other by high-performance liquid chromatography with diode array detection (RP-HPLC‒DAD), for the simultaneous determination of eight synthetic food dyes (Tartrazine, Ponceau 4R, Sunset yellow FCF, Allura red AC, Brilliant blue FCF, Carmoisine, Quinoline yellow, and Patent blue V) in drinks with simple pretreatment were developed and applied to analyze some alcoholic and soft drinks. Detection was performed in the visible range in both cases at wavelengths (nm) of maximum absorbance (420 yellow, 500 red, or 630 blue), depending on the color of each dye. Both developed methods were validated for selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), intra- and interday precision, and recovery, with good results. The RP-HPTLC‒UV/VIS method showed linearity (R2 > 0.998) in the 7–125 µg/mL calibration range, LOD of 0.27–0.92 µg/mL, LOQ of 0.82–1.49 µg/mL, intraday precision (%RSD) of 2.57–7.57, interday precision (%RSD) of 4.21–9.31, and recovery for alcoholic and soft drinks of 86.87–99.87% and 82.70–96.67%, respectively. The RP-HPLC–DAD method showed linearity (R2 > 0.999) in the 1.56–50.0 µg/mL calibration range, LOD of 0.11–0.29 µg/mL, LOQ of 0.32–0.90 µg/mL, intraday precision (%RSD) of 0.13–2.15, interday precision (%RSD) of 0.30–2.47, and recovery of 98.17–101.30% and 88.13–101.9% for alcoholic and soft drinks, respectively. These methods were successfully applied to analyze the 8 synthetic food dyes in 11 (3 alcoholic and 8 soft) drinks from the Romanian market to verify compliance with the label and the maximum permitted level of food dyes in drinks to ensure food safety. [ABSTRACT FROM AUTHOR]

In the present study, a new ion-pair solvent including tetra-n-butyl-ammonium iodide and 1-pentanol was prepared for the first time and it was used for microextraction and UV–Vis spectrophotometric determination of tartrazine (E102), sunset yellow (E110), ponceau 4r (E124), allura red (E129) and brilliant blue (E133). Analytical parameters of the procedure such as pH, concentration of ion-pair solvent and its volume, times of vortex and centrifugation were optimized. Interference effect of matrix ions and dyes were investigated after optimization of the parameters. Limits of detection between 24 and 82 μg L−1 and limits of quantification in the range of 80–275 μg L−1 were determined for the examined dyes. Preconcentration factor was obtained as 15 for each of the dyes. Relative standard deviations were found between 3.2 and 6.1%. Linear dynamic ranges were obtained between 0.28 and 20 µg mL−1 for the determined dyes. Procedure was applied to various food samples including energy drinks, powdered juice samples, syrups and candies. Analyte addition-recovery studies were also performed both for validation of procedure and determination of dye concentrations in the real samples. Food dye contents of real samples were determined between 5.9 and 52.4 μg mL−1 for liquid samples and 6.2 and 135.2 μg g−1 for solid samples with satisfactory recovery results ranging from 93 to 103%. Finally, the greenness of the developed procedure was assessed using two tools, the Green Analytical Procedure Index and Analytical Eco-Scale. [ABSTRACT FROM AUTHOR]

The interaction of 10 synthetic food dyes with human serum albumin (HSA) was investigated using fluorescence spectroscopy, biopartitioning micellar chromatography (BMC) and molecular docking studies. The results obtained by fluorescence spectroscopy indicated that these dyes could strongly quench the intrinsic fluorescence of HSA due to interaction with Trp-214 residue of HSA. The binding constant (Kb) and the number of HSA binding sites were calculated using modified Stern–Volmer equation. BMC as a micellar mobile phase is used as an in vitro system by polyoxyethylene 23 lauryl ether (Brij-35) to predict the Kb of food dyes to HSA. The relationship between the BMC retention data and Kb of food dyes was modeled and the predictive ability of model evaluated. The correlation coefficient (R) and standard error (SE) of developed model were 0.928 and 1.994, respectively. Moreover, molecular docking explorations show that interaction occurs in the subdomain IIA (site I) of HSA. [ABSTRACT FROM AUTHOR]

This work deals with the application of the QuEChERS method for extraction of synthetic food dyes (SFD) from confectionery samples: tartrazine (E102), quinoline yellow (E104), cochineal red A (E124), allura red (E129), patent blue V (E131), and brilliant blue (E133). Extraction conditions, like extraction solvent and its amount, sample amount, the pH adjustment and addition of salt, were optimised. The 5 mL of sample, 2 mL of propan-1-ol as extraction solvent with addition of 0.6 g NaCl, 2.4 g MgSO4, and 0.75 mL 35% HCl were experimentally found to be optimal. Analyses of extracts were performed by liquid chromatography with detection of SFD in the visible region. Recoveries of SFD were in the range of 79.3-100.0% with intra-day precision below 4.6% RSD. The modified QuEChERS method connected with liquid chromatography has been applied to quantify SFD in samples of confectionery (smarties and jellies). The whole procedure was evaluated as a fast method for screening of SFD content in samples of jellies and smarties. [ABSTRACT FROM AUTHOR]